This answer really made me wonder.
I've written CSS before and (usually) I don't really bother to support browsers other than recent firefox and chrome, but in researching I've noticed that, for the exact same CSS property, there are usually at least three different forms which behave identically, and can have the same values, but which all simply have different prefixes for the specific library that implements them.
Here, for example:
-webkit-touch-callout: none;
-webkit-user-select: none;
-khtml-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
With the sole exception of the first one, these only differ by prefix. Why don't maintainers simply change the lexer rule which matches the string "-moz-user-select" to also match "user-select"? Sure, there's the possibility that the author of the original CSS wanted different behavior for Firefox v. other browsers, so "user-select" won't be the same as "-moz-user-select", but the risk of that weird corner case is far outweighed by the advantage, and there are other, arguably better ways to accomplish the browser-specific goal.
If this is already occurring, why do people still use all of these? If they stopped:
- there would be fewer bits clogging the metaphorical pipes of the internet (network latency would go way down, plus individual pages would load faster), and
- people using ancient browsers would be given the impetus they need to update (which they should do for security reasons, anyway)
TL;DR
What would the disadvantage be of everyone using the same naming convention? Why haven't things normalized by now?
user-select
was once part of a working draft, now withdrawn, so what you are seeing is just browser-specific properties with no definitions beyond those that each vendor might provide (in some format, usually in informal and inexact language).